This conference is designed to convene a gathering of nationally recognized health services researchers to discuss methodological issues in researching possible geographical barriers to health services in managed care for minority subpopulations. As greater numbers of minority populations join managed care organizations (both commercial and Medicaid), questions of accessing health services arise. It does little good to join a managed care plan if there are few or no providers contracted with one's plan in the area (Friedman 1994). What are the potential ways of measuring limitations in access to health care by minority populations within the managed care environment? How good are various measures (e.g., physician-patient ratios, distance to doctor's office, public transportation routes) at assessing whether there are adequate services provided within small geographic areas, such as urban neighborhoods? In assessing the quality of a managed care organization, can we devise composite variables to measure the availability of health services by small geographic units? Adjusting for this variable is likely to be of some importance in evaluating plan performance. In addition, it is unclear whether market forces alone will sufficiently redistribute the physician workforce to adequately staff areas of greatest need (Moore GT 1994). Will additional information increase the probability that the market will solve problems of physician maldistribution? This issue is likely to be of some importance in future public policy decision-making (Wennberg JE 1993). The significance of the proposed conference lies in the fact that the methods for measuring physician participation in managed care plans and for quantifying the availability of medical care in urban areas are at present not well defined. Opening this discussion could have important ramifications in how access to care is studied in the future, as well helping to safeguard health care services to vulnerable populations within the managed care environment.